title: Microbial content of household dust associated with exhaled NO in asthmatic children.
abstract: Exhaled nitric oxide (eNO) is increasingly used as a non-invasive measure of airway inflammation. Despite this, little information exists regarding the potential effects of indoor microbial components on eNO. We determined the influence of microbial contaminants in house dust and other indoor environmental characteristics on eNO levels in seven-year-olds with and without a physician-diagnosis of asthma. The study included 158 children recruited from a birth cohort study, and 32 were physician-diagnosed as asthmatic. The relationship between eNO levels and exposures to home dust streptomycetes, endotoxin, and molds was investigated. Streptomycetes and endotoxin were analyzed both as loads and concentrations in separate models. Dog, cat, and dust mite allergens also were evaluated. In the multivariate exposure models, high streptomycetes loads and concentrations were significantly associated with a decrease in eNO levels in asthmatic (p<0.001) but not in healthy children. The presence of dog allergen, however, was associated with increased levels of eNO (p=0.001). Dust endotoxin was not significant. The relationship between eNO and indoor exposure to common outdoor molds was u-shaped. In non-asthmatic children, none of the exposure variables was significantly associated with eNO levels. To our knowledge, this is the first study demonstrating a significant association between microbial components in the indoor environment and eNO levels in asthmatic children. This study demonstrates the importance of simultaneously assessing multiple home exposures of asthmatic children to better understand opposing effects. Common components of the indoor Streptomyces community may beneficially influence airway inflammation.
authors.affiliation: Department of Environmental Health, University of Cincinnati, P.O. Box 670056, Cincinnati, OH 45267-0056, USA.
authors.forename: Elisabet
authors.initials: E
authors.lastname: Johansson
authors.forename: Tiina
authors.initials: T
authors.lastname: Reponen
authors.forename: Stephen
authors.initials: S
authors.lastname: Vesper
authors.forename: Linda
authors.initials: L
authors.lastname: Levin
authors.forename: James
authors.initials: J
authors.lastname: Lockey
authors.forename: Patrick
authors.initials: P
authors.lastname: Ryan
authors.forename: David I
authors.initials: DI
authors.lastname: Bernstein
authors.forename: Manuel
authors.initials: M
authors.lastname: Villareal
authors.forename: Gurjit K
authors.initials: GK
authors.lastname: Khurana Hershey
authors.forename: Chris
authors.initials: C
authors.lastname: Schaffer
authors.forename: Grace
authors.initials: G
authors.lastname: Lemasters
mesh_terms: D016902:Air Pollution, Indoor / Q000032:analysis; D000485:Allergens / Q000032:analysis; D000818:Animals; D001249:Asthma / Q000503:physiopathology*; D002415:Cats; D002648:Child; D004285:Dogs; D004391:Dust / Q000032:analysis*; D004731:Endotoxins / Q000032:analysis*; D004781:Environmental Exposure; D045853:Exhalation; D005260:Female; D005658:Fungi / Q000302:isolation & purification*; D006798:Housing; D006801:Humans; D008297:Male; D009569:Nitric Oxide / Q000032:analysis*; D039981:Pyroglyphidae / Q000276:immunology; D013302:Streptomyces / Q000302:isolation & purification*
chemical_list: D000485:Allergens; D004391:Dust; D004731:Endotoxins; D009569:Nitric Oxide
keywords: Allergens; Asthma; Children; ERMI; Environmental Relative Moldiness Index; Exhaled nitric oxide; LOD; Mold; SLG2; SPT; Streptomycetes; eNO; exhaled nitric oxide; limit of detection; skin prick test; sum of log-transformed Group 2 mold concentrations